A semiconductor die usually has a plurality of contact pads via which electrical signals may be fed to or received from the die. Various methods of electrically connecting the die to the substrates are known in the art. Such methods include wire bonding and flip chip bonding. For packages, it is notably known to arrange a redistribution layer inside the package, on one side of the die. A redistribution layer serves as an interface between contact pads of the die and contact pads of the substrate. A redistribution layer may be stacked directly on the die. More generally, a connection unit may be arranged as an interface between the die and the substrate. The connection unit may comprise a stack of several redistribution layers stacked atop each other.
A die may also be referred to as a chip. A die may contain one or more integrated circuits. A die may be housed in a housing. An assembly comprising a housing and one or more dies arranged therein may also be referred to as a chip. An assembly comprising one or more chips connected to a substrate is known as a package. The fabrication of such packages is known as packaging.
One such packaging technique is known as redistributed chip packaging (RCP). Redistributed chip packaging is notably used for various applications. The usable frequency range can go from DC beyond hundreds of gigahertz, as in radar transmission or reception circuits, for example. RCP notably allows an integration of multiple chips in one package. A single package may include several redistribution layers, typically up to five redistribution layers. An integration of lumped passive components is also possible. Such passive components may include, for example, quartz crystals, capacitors, and surface-mounted devices (SMD).